This invention relates to a so-called four way reversing valve finding particular use, for example, in a heat pump for selectively switching operation of the heat pump between its heating and cooling modes of operation. More specifically, this invention relates to an improved four way reversing valve having improved refrigerant flow characteristics and further having significantly less flow losses (i.e., pressure drop) than prior art reversing valves.
More generally, a heat pump system is a refrigeration system which in essence includes a compressor, a first air-to-air heat exchange coil located within the space (e.g., a home) to be heated or cooled and a second air-to-air heat exchange coil located outside the space (e.g., out-of-doors). A reversing valve is interposed in the refrigerant lines connecting the coils to the compressor for directing the flow of high pressure refrigerant to either the inside or outside coil so as to either heat or cool the space. When operated for in its cooling mode, the heat pump functions as an air conditioner, and when operated in its heating mode, the heat pump efficiently and economically elevates the potential of low grade heat in the outside air (or other heat source) to a level useful in heating the inside space.
In the typical air-to-air heat pump, both refrigerant heat exchangers (i.e., the inside and outside coils) are sized and designed to serve either as an evaporator or a condenser according to the operational mode chosen for the heat pump. Typically, a four way reversing valve is utilized to select the operational mode of the heat pump. These valves include four refrigerant connections, viz, a so-called discharge port intended to be connected to the discharge or high pressure side of the compressor, a suction port adapted to be connected to the suction or inlet side of the compresser, and a pair of combined inlet/outlet ports each of which is intended to be connected to a respective coil. Of course, the coils are interconnected so that refrigerant flows from one to another and appropriate expansion valves are provided.
Prior art reversing valves typically include a valve body in which the four above-noted ports or connections are provided. A slide member having a number of flow passages therein is provided in an axial bore of the valve body and is slidably movable in the body under the control of a solenoid actuated pilot valve so as to direct the discharge of the compressor either to the inside coil or the outside coil and to simultaneously direct the low pressure refrigerant from either the outside or inside coil to the suction side of the compressor so that the system may either be operated in its heating or cooling mode.
Reference may be made to such prior U.S. Pat. Nos. as 2,933,107, 3,004,557 and 3,037,525 which are co-assigned to the assignee of the present invention and which disclose several prior art four-way change over or reversing valves utilized in heat pump systems. While these and other prior art valves have operated well for their intended purposes, they are known to cause a significant pressure drop in the refrigerant flowing therethrough which, of course, lowers the overall efficiency of the entire heat pump system. In order to hold the pressure drop at a manageable limit, prior art reversing valves are typically of a relatively large size and weight.
Among the several objects and features of the present invention may be noted the provision of a reversing valve which in principle and operation is similar to prior art reversing valves and yet which suprisingly exerts significantly less restriction to the flow of refrigerant therethrough at both the suction and discharge sides of the valve;
The provision of such a valve which may be significantly smaller and of lighter weight (and hence less costly) than comparable prior art valves and yet which is capable of handling comparable flow rates of refrigerant therethrough with comparable flow losses and pressure drops; and, in general;
The provision of such a valve which is of simple and rugged construction, which is easy and economical to manufacture, and which is reliable in operation.
Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.